content/renderer/media/video_capture_impl.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // VideoCaptureImpl represents a capture device in renderer process. It provides
   6 // interfaces for clients to Start/Stop capture. It also communicates to clients
   7 // when buffer is ready, state of capture device is changed.
   8
   9 // VideoCaptureImpl is also a delegate of VideoCaptureMessageFilter which relays
  10 // operation of a capture device to the browser process and receives responses
  11 // from browser process.
  12 //
  13 // All public methods of VideoCaptureImpl can be called on any thread.
  14 // Internally it runs on the IO thread. Clients of this class implement
  15 // interface media::VideoCapture::EventHandler which is called only on the IO
  16 // thread.
  17 //
  18 // Implementation note: tasks are posted bound to Unretained(this) to the I/O
  19 // thread and this is safe (even though the I/O thread is scoped to the renderer
  20 // process) because VideoCaptureImplManager only triggers deletion of its
  21 // VideoCaptureImpl's by calling DeInit which detours through the I/O thread, so
  22 // as long as nobody posts tasks after the DeInit() call is made, it is
  23 // guaranteed none of these Unretained posted tasks will dangle after the delete
  24 // goes through. The "as long as" is guaranteed by clients of
  25 // VideoCaptureImplManager not using devices after they've released
  26 // VideoCaptureHandle, which is a wrapper of this object.
  27
  28 #ifndef CONTENT_RENDERER_MEDIA_VIDEO_CAPTURE_IMPL_H_
  29 #define CONTENT_RENDERER_MEDIA_VIDEO_CAPTURE_IMPL_H_
  30
  31 #include <list>
  32 #include <map>
  33
  34 #include "base/memory/weak_ptr.h"
  35 #include "content/common/content_export.h"
  36 #include "content/common/media/video_capture.h"
  37 #include "content/renderer/media/video_capture_message_filter.h"
  38 #include "media/video/capture/video_capture.h"
  39 #include "media/video/capture/video_capture_types.h"
  40
  41 namespace base {
  42 class MessageLoopProxy;
  43 }
  44
  45 namespace content {
  46
  47 class CONTENT_EXPORT VideoCaptureImpl
  48     : public media::VideoCapture, public VideoCaptureMessageFilter::Delegate {
  49  public:
  50   VideoCaptureImpl(media::VideoCaptureSessionId session_id,
  51                    VideoCaptureMessageFilter* filter);
  52   virtual ~VideoCaptureImpl();
  53
  54   // Start listening to IPC messages.
  55   void Init();
  56
  57   // Stop listening to IPC messages. Call |done_cb| when done.
  58   void DeInit(base::Closure done_cb);
  59
  60   // Stop/resume delivering video frames to clients, based on flag |suspend|.
  61   void SuspendCapture(bool suspend);
  62
  63   // media::VideoCapture interface.
  64   virtual void StartCapture(
  65       media::VideoCapture::EventHandler* handler,
  66       const media::VideoCaptureParams& params) OVERRIDE;
  67   virtual void StopCapture(media::VideoCapture::EventHandler* handler) OVERRIDE;
  68   virtual bool CaptureStarted() OVERRIDE;
  69   virtual int CaptureFrameRate() OVERRIDE;
  70
  71   media::VideoCaptureSessionId session_id() const { return session_id_; }
  72
  73  private:
  74   friend class VideoCaptureImplTest;
  75   friend class MockVideoCaptureImpl;
  76
  77   class ClientBuffer;
  78   typedef std::map<media::VideoCapture::EventHandler*,
  79                    media::VideoCaptureParams> ClientInfo;
  80
  81   void InitOnIOThread();
  82   void DeInitOnIOThread(base::Closure done_cb);
  83   void SuspendCaptureOnIOThread(bool suspend);
  84   void StartCaptureOnIOThread(
  85       media::VideoCapture::EventHandler* handler,
  86       const media::VideoCaptureParams& params);
  87   void StopCaptureOnIOThread(media::VideoCapture::EventHandler* handler);
  88
  89   // VideoCaptureMessageFilter::Delegate interface.
  90   virtual void OnBufferCreated(base::SharedMemoryHandle handle,
  91                                int length,
  92                                int buffer_id) OVERRIDE;
  93   virtual void OnBufferDestroyed(int buffer_id) OVERRIDE;
  94   virtual void OnBufferReceived(
  95       int buffer_id,
  96       base::TimeTicks timestamp,
  97       const media::VideoCaptureFormat& format) OVERRIDE;
  98   virtual void OnStateChanged(VideoCaptureState state) OVERRIDE;
  99   virtual void OnDelegateAdded(int32 device_id) OVERRIDE;
 100
 101   // Sends an IPC message to browser process when all clients are done with the
 102   // buffer.
 103   void OnClientBufferFinished(
 104       int buffer_id,
 105       const scoped_refptr<ClientBuffer>& buffer);
 106
 107   void StopDevice();
 108   void RestartCapture();
 109   void StartCaptureInternal();
 110   virtual void Send(IPC::Message* message);
 111
 112   // Helpers.
 113   bool RemoveClient(media::VideoCapture::EventHandler* handler,
 114                     ClientInfo* clients);
 115
 116   const scoped_refptr<VideoCaptureMessageFilter> message_filter_;
 117   const scoped_refptr<base::MessageLoopProxy> io_message_loop_proxy_;
 118   int device_id_;
 119   const int session_id_;
 120
 121   // Buffers available for sending to the client.
 122   typedef std::map<int32, scoped_refptr<ClientBuffer> > ClientBufferMap;
 123   ClientBufferMap client_buffers_;
 124
 125   ClientInfo clients_;
 126   ClientInfo clients_pending_on_filter_;
 127   ClientInfo clients_pending_on_restart_;
 128
 129   // Member params_ represents the video format requested by the
 130   // client to this class via StartCapture().
 131   media::VideoCaptureParams params_;
 132
 133   // The device's video capture format sent from browser process side.
 134   media::VideoCaptureFormat last_frame_format_;
 135
 136   // The device's first captured frame timestamp sent from browser process side.
 137   base::TimeTicks first_frame_timestamp_;
 138
 139   bool suspended_;
 140   VideoCaptureState state_;
 141
 142   // WeakPtrFactory pointing back to |this| object, for use with
 143   // media::VideoFrames constructed in OnBufferReceived() from buffers cached
 144   // in |client_buffers_|.
 145   base::WeakPtrFactory<VideoCaptureImpl> weak_this_factory_;
 146
 147   DISALLOW_COPY_AND_ASSIGN(VideoCaptureImpl);
 148 };
 149
 150 }  // namespace content
 151
 152 #endif  // CONTENT_RENDERER_MEDIA_VIDEO_CAPTURE_IMPL_H_